Note that page state does not persist across wiki rebuilds, only across
wiki updates.
+### %wikistate
+
+The `%wikistate` hash can be used by a plugin to store persistant state
+that is not bound to any one page. To set a value, use
+`$wikistate{$id}{$key}=$value, where `$value` is anything Storable can
+serialize, `$key` is any string you like, and `$id` must be the same as the
+"id" parameter passed to `hook()` when registering the plugin, so that the
+state can be dropped if the plugin is no longer used.
+
### Other variables
If your plugin needs to access data about other pages in the wiki. It can
Given the name of a source file, returns the name of the wiki page
that corresponds to that file.
+#### `pagetitle($)`
+
+Give the name of a wiki page, returns a version suitable to be displayed as
+the page's title. This is accomplished by de-escaping escaped characters in
+the page name. "_" is replaced with a space, and '__NN__' is replaced by
+the UTF character with code NN.
+
+#### `titlepage($)`
+
+This performs the inverse of `pagetitle`, ie, it converts a page title into
+a wiki page name.
+
+#### `linkpage($)`
+
+This converts text that could have been entered by the user as a
+[[WikiLink]] into a wiki page name.
+
#### `srcfile($;$)`
Given the name of a source file in the wiki, searches for the file in